(1) Field of the Invention
This invention relates to circuit board assemblies as used, for example, in an instrument cluster of a motor vehicle to effect internal electrical connections between the individual instruments and a removable plug connected to a wiring harness.
(2) Prior Art
Conventional circuit boards used in such instrument clusters carry a flexible circuit sheet on one surface. This sheet is composed of a number of strips of electrically conductive material, usually copper, mounted on a film of insulating material. A protective coating of insulating material is usually applied over the strips of conductive material. A contact portion of the sheet, usually along one or more edges of the sheet, is however free from insulating material so that the copper strips are exposed for electrical connection to a wiring harness. The circuit sheet is mounted on a rear surface of the circuit board and the contact portion is bent over an edge of the board and lies against a supporting surface which extends forwardly away from the rear surface. Electrical connections to the circuit sheet are made by inserting a plug connected to a wiring harness into the circuit board from the rear side of the board so that contacts in the plug engage with the exposed strips of conductive material on the contact portion of the circuit sheet.
Although this arrangement operates satisfactorily when the plug is connected to the circuit board from the rear of the board, it has been found that a similar arrangement cannot be used when the circuit is mounted on the front of the board because the insertion of the plug into the board tends to strip the circuit sheet from the front surface of the board.